1. Field of the Invention
The present invention relates to a jet vane thrust vector control (JV-TVC) system, and more particularly to, a JV-TVC system which can obtain high angle of attack maneuvers and perform stabilized attitude control in rapid pitchover toward a target direction after launching a missile.
2. Description of the Background Art
In general, aerodynamic wings are installed on a missile to control the direction of the missile. Since a speed is low in launching the missile, it is not easy to control the direction of the missile by the aerodynamic wings.
There are thus demands for different means for controlling the direction of the missile in launching the missile. For this, a thrust vector control (TVC) system has been developed.
The missile using the JV-TVC system can not only control the direction but also be vertically launched in respect of operation. Accordingly, it is possible to omnidirectionally monitor the missile, provide a rapid pitch-over the missile after launching, and enter the missile into an optimum orbit within a short time according to the purpose of the missile.
The application methods of the TVC system can be achieved, in general, with liquid injection, a movable nozzle and a mechanical deflector method.
Among the methods, a mechanical TVC method achieving miniaturization such as jet vane, jetavator and jet tab has been widely used for the TVC system of the tactical missile.
A JV-TVC method that can provide 3-axis control of pitch, yaw and roll in one nozzle in missile flight has been widely used for the general TVC system.
Exemplary missiles using the JV-TVC system include VLASROC (USA), SEA SPARROW (USA), BARAK (Israel), MICA (France) and S-300 (Russia) et al.
The JV-TVC system controls a thrust vector by adjusting flame gas flow, by installing generally four jet vanes on an inside surface or at an end of a nozzle exit unit of a propulsion system and changing the angles of the jet vanes in combustion of the propulsion system.
In the conventional art, three jet vanes are individually installed on a nozzle, and the inner wall of the nozzle is formed in a conical shape. It is thus difficult to precisely assemble the system and control the thrust vector.
In addition to that the inner wall of the nozzle is formed in a conical shape, the root periphery of the jet vane adjacent to the inner wall of the nozzle does not make a right angle with a jet vane shaft. Therefore, the rotational angle of the jet vane inside the nozzle is restricted. A relatively large gap must be formed between the root periphery of the jet vane adjacent to the inner wall of the nozzle and the inner wall of the nozzle. Moreover, the gap must be precisely designed and formed according to the inside diameter of the inner wall of the nozzle and the size of the jet vane. It makes it more difficult to manufacture and assemble the system.
The JV-TVC system must satisfy performance requirements of a rocket or a missile. In the patent of Faupell et al., since the relatively large gap is formed between the root periphery of the jet vane and the inner wall of the nozzle and the jet vane shaft is simply supported through an axial hole formed in a straight line on an exit cone liner and an exit cone body composing the nozzle, heat of flames ejected from the nozzle is easily transmitted to a bearing for supporting the jet vane shaft to the exit cone body and an O-ring for maintaining airtightness through the clearance and a clearance between the jet vane shaft and the axial hole. Therefore, the bearing and the O-ring are damaged for a designated flight time, so that the thrust vector of the rocket or the missile cannot be precisely controlled.
As a result, the JV-TVC system is disadvantageous in the thermal respect because the jet vanes are directly exposed to the high temperature combustion gas. Ablation and thrust loss (3˜5%) are caused for a combustion time. Especially, design techniques such as mutual assembly between the jet vanes and the peripheral devices and hermetical sealing are required for precise and reliable control.
The most important factors of the JV-TVC system researches include development of anti-erosion materials, design of jet vanes having thermal and fluid dynamics properties to flame gas, and design of related component mechanism. A method for preventing thermal locking or sticking between a jet vane shaft and a housing by heat transfer in combustion and a method for hermetically sealing a fastening assembly part by flame gas are also essential.
The existing design mechanism of the JV-TVC system has many problems in design techniques considering actual operation environments. Especially, the existing design mechanism does not have reliability in component assembly design.